ITINERANT MAGNETISM OF FCC-IRON AND DISORDERED IRON NICKEL-INVAR ALLOYS

We apply a tight-binding method for the self-consistent calculation of the itinerant magnetic properties of transition metal alloys to face-centered cubic iron and disordered iron-nickel alloys with particular emphasis on the Invar region around and above 65% Fe. We find an increase of the magnetization with decreasing density for every material. For fcc iron at high densities we obtain ferrimagnetic and spin-glass like states. The magnetization curve of Fe/Ni alloys is very well reproduced in the whole concentration region. The drastic change of the magnetization curve in the Invar region is found to follow from the concentrations- and environment-dependence of the Fe moments.